Fuse holder



'Dec. 15, 1942. I sfiE 2,305,041

FfiSE HOLDER Filed Aug. 4, 1940 2 Sheets-Sheet l INVENTOR. Y HENRY M. ST/EGL/TZ 1942- H. M. STIEGLITZ ,30

FUSE HOLDER- Filed Aug. 4, 1940 2 Sheets-Sheet 2 F13 4 INVENTOR:

HENRY ST/EeL/TZ Patented Dec. 15, 1942 rose nomaa ilenry M. Stiegiita, St. Louis, Mo., assignor to Frank Adam Electric Company, St. Louis, Mo., a corporation of Missouri Application August 4, .1940, Serial No. 351,389

- 12 Claims.

This invention relates to improvements in fuse holders. More particularly, the invention relates to improvements in fuse holders that utilize a resilient cam to maintain intimate contact between the fuse terminal and the fuse holder.

It is one object of the invention to provide a fuse holder of this type that is simple and easy to manufacture.

In many of the fuse holders now in use, the pressure between the fuse holder and the fuse terminal that is necessary to an efficient electrical connection therebetween', is dependent upon the resilient characteristics of one or more clips that are similar to a leaf spring. The fuse is forced between a clip and a stop, or is forced between two. clips, and is held there by the pressure which the clip or clips exert on it. In this type of fuse holder, the effectiveness of the electrical connection between the fuse terminal and the holder is dependent upon the elastic properties of the material in the clip. In such a fuse holder, the current passes through the clip and it is therefore desirable to have clips of material which has low electrical resistance. Where the fuse clips are made of material that has low electrical resistance, they do not have the resiliency characteristics necessary to the maintenance of adequate pressure between the fuse and the fuse holder. This results from the fact that metals which have low electrical resistance ordinarily have rather poor resiliency characteristics. In many fuse holders of this type, the clip is supported at one end only, and acts as a cantilever beam. Where such a design is used, each of the fuse clips is susceptible to possible abuse at its free end. Such abuse, quite likely, might result in a spreading of the clips and a resultant decrease in pressure between the fuse terminal and the clips. This would result in a decrease in the electrical efllciency of the connection between the fuse terminal and the holder. If, in an effort to prevent the bending or spreading of the clips and the resulting loss of electrical efficiency, the clips are made of a material resilient enough so that abuse will not alter the distances between the clips or between a clip and a stop, the material will probably have greater electrical resistance than is desired. Another way in which the clips might be protected from spreading is the use of clips of low resistance metal that are large enough and massive enough to withstand considerable abuse. Such clips would not be entirely satisfactory because their massiveness and stiffness would prevent the ready insertion and removal of the fuse from the fuse holder. It can be seen, therefore, that fuse holders which attain pressure between the fuse terminal and the fuse holder by utilization of the resilient characteristics of clips are quite objectionable. The invention obviates the objections outlined above by providing a fuse holder which attains pressure between the fuse terminal and the fuse holder without the use of clips. It is, therefore, an object of the present invention to provide a fuse holder which attains adequate pressure between the fuse holder and the fuse terminal without the use of clips.

Another type of fuse holder in use is one which comprises a solid cam that bears against the fuse terminal. Pressure between the cam and the fuse terminal is maintained by the bending or compression of the fuse terminal. Becausethe metal of which the fuse terminal is made has low resiliency characteristics, the bending and compression thereof is deleterious. The invention obviates any bending or compression of the fuse terminal by providing a resilient cam that bends and maintains adequate pressure between the v fuse terminal and fuse holder by reason of its bending. It is, therefore, an object of the present invention to provide a fuse holder wherein pressure between the fuse terminal and fuse holder is maintained by employment of a flexible cam.

Still another type of fuse holder in use is one which comprises a U-shaped clamp, a support on which the fuse terminal is placed, and a cam that is journaled in the support. In this type of holder, the cam is used to draw the U-shaped clamp into intimate engagement with the fuse terminal. Since the axis of rotation of the cam is fixed, the point of contact between the fuse terminal and the U-shaped clamp must move, with relation to the fixed center, as the cam is rotated. The larger the eccentricity of the cam and, therefore, the larger the motion of the U-shaped clamp, the greater the length of the line of contact between the fuse terminal and fuse holder must be. Since a long line of contact would tend to cause the U-shaped clamp to tilt and thereby prevent the movement of the cam to the full on position, only a small eccentricity can be had. A small eccentricity restricts the movement of the U-shaped clamp and increases the difflculties met in inserting and removing the fuse from the fuse holder. The invention obviates this objection by providing a cam that is rotatably secured to the u-shaped clamp instead of the support. Such an arangement permits an increase in the eccentricity of the cam with a decrease in the length of the line of contact between the fuse and the U-shaped clamp. It is, therefore, an object of the invention to provide a fuse holder having a U-shaped clamp and a cam that are rotatably secured to each other.

The fuse holders that are in use today are usually secured to a connector which, in turn, is secured to a base of insulating material. Such construction is rather complicated and requires the expenditure of a good deal of time in assembling the various parts. Where the fuse holders are made on a production line, the necessity of securing the parts to each other by bolts or screws increases the time required. An increase of time on the production line means increased cost. The invention permits a reduction in the cost of manufacture by providing formed recesses in insulating. bases that removably support portions of the fuse holder. It is, therefore, an object of the present invention to provide an insulating base for fuse holders having preformed recesses therein that removably support the fuse holder.

Other objects and advantages of the invention will be shown and described in the drawings an accompanying description.

The drawings and description show preferred forms of the invention, but it is to be understood that the drawings and accompanying description do not limit the invention and that the invention will be defined by the appended claims.

In the drawings,

Fig. 1 is a perspective view of a base of insulating material that supports two fuse holders made in accordance with the principles of the invention; r

Fig. 2 is a perspective view of the fuse terminal support, that is an element of the fuse holder;

Fig. 3 is a perspective view of the U-shaped clamp that engages and holds the fuse terminal.

Fig. 4 is a bearing plate that engages the under side of the fuse terminal support shown in Fig. 2;

Fig. 5 is a perspective view of the cam used in the invention;

Fig. 6 is a cross-sectional view through the base of insulating material shown in Fig. l, and shows the parts of the invention as they are assembled prior to the clamping oi the fuse in the fuse holder:

Fig. 7 is a cross-sectional view through the base of insulating material shown in Fig. 1, and shows the parts of the invention as they are assembled when the fuse is clamped in the fuse holder;

Fig. 8 is a perspective view of a modified form of the invention;

Fig. 9 is a side and end view of the cam used in the modified form of the invention shown inv Fig. 8;

Fig. 10 is a perspective view of the fuse terminal support used in the fuse holder shown in Fig. 8;

Fig. 12; and I Fig. 15 is a perspective view of the flexible-cam used in the fuse holder shown in Fig. 12.

Referring to the drawings in detail, a base of insulating material is denoted by the numeral 20. The base has recesses 22 formed therein that removably support fuse holders made in accordance with the principles of the invention. The base 20 also has openings 24 therethrough to permit the securing of the fuse holder to the base. A fuse terminal support 26 having a concave portion at one end that engages a fuse terminal, is held to the base 20 by a bolt that engages one of the holes 24 in the base and a threaded hole 28 in the support 26. The support 26 may be provided with an extruded portion 21 that serves as a stop and limits the longitudinal movement of a fuse supported by the holder. A U-shaped clamp 29 having two holes 30 at the lower extremities thereof may be provided with a stop 32. A hearing member 34 may also be provided for use with the invention. This bearing member is preferably U-shaped and has a longitudinal opening 36 in one side thereof. A cam 38 of flexible material is provided that is substantially L-shaped. In one arm of the cam, there is a bent portion 40 that is eccentric to the axis of that arm. The cam 36 is supported and journaled in the holes 30 of the U-shaped clamp 29, in such a manner that the eccentric portion of the cam is between the arms of the U-shaped clamp 29. The eccentric portion 40 of the cam 38 engages and is covered by the bearing member 34, which is removably supported by the recesses 22 in the base 20 of insulating material. The combination of the U-shaped clamp 29, cam 38, and bearing member 34, is maintained in assembled relation with the base 20 by bolting fuse terminal support 26 to the base 26. The stop 32 on the U-shaped clamp 29 limits the move ment of the cam 38 and maintains the cam in the position of greatest eccentricity whenever it is in the clamping position. The connection between the parts is such that the U-shaped clamp 29 may be rotated back from the fuse terminal support to permit ready insertion of a fuse S0, and may then be rotated to the proper position where it is moved into intimate engagement with fuse to by the rotation of cam 38. The provision of a cam that is supported by the U-shaped clamp and not by the fuse terminal support, permits the use of a cam having a large eccentricity since the U-shaped clamp and the cam both move toward the fuse terminal. Such an arrangement gives a short line of contact between the fuse terminal and the U-shaped clamp, and between the cam and the bearing member, instead of a long line of contact between the U-shaped clamp and the fuse terminal. The invention halves the line of contact between the fuse terminal and the U-shaped clamp and reduces any tendency to tilt.

A modified form of the invention is shown in Fig. 8 that consists of a hoop 42, which supports a U-shaped cam 44 of flexible material. This hoop is removably supported in a groove 46 in a base 48 of insulating material. The hoop is secured to the base 48 by the bolting of fuse terminal support 50 to the base. Blocks 52 of insulating material are secured to the base 48 and serve to limit the movement of the hoop 42. The pressure between the fuse terminals of fuse 40 and the fuse support 50 is secured by a spreading of the legs of the U-shaped cam 44. The cam 44 is provided with an upstanding portion 45 that enables an operator to rotate the cam.

Another form of the invention is shown in Fig. 12. This form of the invention is quite similar to the form shown in Fig. 1 except that this form is useful with fuses having blade type terminals. In this form of the invention, the U-shaped clamp 29 has a flat upper section and the bearing member 35 is flat. In addition, the bearing member 35 has a projection 54 thereon that engages an opening 56 in the fuse terminal support 58 and thereby maintains the bearing member and the fuse terminal support in assembled relation. The bearing member has projections 60 on the sides thereof that cooperate with cam 38 to maintain the U-shaped clamp 29, bearing member 35, and cam 38 in assembled relation.

Where desired, three or more recesses that receive and support fuse holders may be formed in the base 20 of insulating material. By use of such a base, a fuse holder combination may be had which can be used on fuses of different lengths. Such an arrangement materially lessens the cost of manufacture of fuse holders, since it permits one base to serve for two different installations.

Whereas a few preferred embodiments of the invention have been shown and described in the drawings and accompanying description, it is obvious to those skilled in the art that various changes may be made in the 'form of the invention without altering the scope of the invention.

By use of the invention, a fuse holder may be had which is not dependent on the resilient characteristics of the contact metal to maintain adequate pressure between the fuse terminal and the fuse holder. The invention also provides a fuse holder that may have a large eccentricity with a relatively short line of contact between the fuse terminal and the U-shaped clamp. It can be seen, therefore, that the invention provides a simple but eflicient fuse holder.

What I claim is:

1. A fuse holder comprising a base of insulating material, a fuse terminal supporting contact on said base, a recess in said base under the fuse terminal supporting contact, a cam positioned in the recess under the fuse terminal supporting contact provided with a handle adapted to rotate it, a clamp member adapted to engage the top side of a fuse terminal, Joumaled on said cam member, rotation of the cam bringing the clamp member into clamping engagement with the top side of a fuse terminal.

2. A fuse holder comprising a base of insulating material, a fuse terminal supporting contact on said base, a recess in said base under the fuse terminal supporting contact, a bearing member supported and positioned in said recess, a cam positioned in said bearing member, a clamp member Journaled on the cam and adapted to extend up and engage the top side of a fuse terminal, rotation of the cam bringing the clamp member into clamping engagement with the top side of a fuse terminal.

3. A fuse holder having a base of insulating material, oppositely disposed fuse terminal supports thereon, a recess under one of said fuse terminal supports and a plurality of recesses under the other fuse terminal support, a cam member supported and positioned in one of the recesses below each fuse terminal support, clamp members adapted to engage the top side of a fuse terminal journaled on the cam members, each of the recesses under the one fuse terminal support being adapted to support and position a cam member and its associated clamp member to thereby vary the distance between opposite clamp members and allow fuses of various capacities to be accommodated on the same size insulating base.

4. A fuse holder adapted to be supported by a recess in a base of insulating material, comprising a fuse terminal support, said fuse terminal support being adapted to be secured to said base of insulating material, a cam formed of resilient material that bends when it is rotated into the clamping position and thereby provides adequate pressure between a fuse terminal and the fuse terminal support, and a hoop that engages the upper portion of a fuse terminal, said hoop being movahaving no positive connection therewith, said cam being journaled in and supported solely by the hoop and having no positive connection with the fuse terminal support, the lower portions of said hoop being adapted to be positioned in the recess in the base of insulating material.

5. A fuse holder comprising a fuse terminal support, a bearing member adapted to engage the under side of the fuse terminal support, a cam formed of resilient material that bends when it is rotated into the clamping position and thereby provides adequate pressure between a fuse terminal and the fuse terminal support, a substantially U-shaped clamp that engages the upper portion of a fuse terminal and cooperates with the bearing member and the cam to hold the fuse terminal securely to the fuse terminal support, said U-shaped clamp being movable with respect to the fuse terminal support and having no positive connection therewith, said cam being journaled in and supported solely by the U-shaped clamp and having no positive connection with the fuse terminal support, and a supporting base having a plurality of recesses therein, said recesses being adapted to removably support the bearing member and the substantially U-shaped clamp.

6. A fuse holder adapted to be supported by a recess in a base of insulating material, comprising a fuse terminal support, said fuse terminal support being adapted to be secured to said base of insulating material, a cam, and a hoop that engages the upper portion of a fuse terminal and cooperates with the fuseterminal support and the cam to hold the fuse terminal securely to the terminal support, thereby maintaining adequate pressure therebetween, said hoop being movable with respect to the fuse terminal support and having no positive connection therewith, said cam being journaled in and supported solely by the hoop and having no positive connection with the fuse terminal support, the lower portions of said hoop being adapted to be positioned in the recess in the base of insulating material.

7. A fuse holder adapted to be supported by a recess in a base of insulating material, comprising a fuse terminal support, said fuse terminal support being adapted to besecured to said base of insulating material, a bearing member adapted to engage the under side of the fuse terminal support, said bearing member being adapted to be supported by the recess in said base of insulating materiaLa cam formed of resilient material that bends when it is rotated into the clamping posi tion and thereby provides adequate pressure between a fuse terminal and the fuse terminal support, and a substantially U-shaped clamp that ble with respect to the fuse terminal support and engages the upper portion of a fuse terminal and cooperates with the bearing member and the cam to hold the fuse terminal securely to the fuse terminal support, said U-shaped clamp being movable with respect to the fuse terminal support and having no positive connection therewith, said cam being journaled in and supported solely by the U-shaped clamp and having no positive connection with the fuse terminal support, the lower portions of said U-shaped clamp and cam being adapted to be positioned in the recess in the base of insulating material.

8. A fuse holder adapted to be supported by a recess in a base of insulating material, comprising a fuse terminal support, said fuse terminal support being adapted to be secured to said base of insulating material, a bearing member adapted to engage the under side of the fuse terminal support, said bearing member being adapted to be supported by the recess in said base of insulating material, a cam, and a substantially U- shaped clamp that engages the upper portion of a fuse terminal and cooperates with the bearing member, fuse terminal support, and the cam to hold the fuse terminal securely to the fuse terminal support thereby maintaining adequate pressure therebetween, said U-shaped clamp being movable with respect to the fuse terminal support and having no positive connection therewith, said cam being journaled in and supported solely by the U-shaped clamp and having no positive connection with the fuse terminal support, the lower portions of said U-shaped clamp and cam being adapted to be positioned in the recess in the base of insulating material, the securement of the fuse terminal support to the base of insulating material being adapted to maintain the elements of the fuse holder in assembled relation.

9. A fuse holder adapted to be supported by a recess in a base of insulating material, comprising a fuse terminal support, said fuse terminal support being adapted to be secured to said base of insulating material, a cam, and a substantially U-shaped clamp that engages the upper portion of a fuse terminal and cooperates with the fuse terminal support and the cam to hold the fuse terminal securely to the fuse terminal support thereby maintaining adequate pressure therebetween, said U-shaped clamp being movable with respect to the fuse terminal support and having no positive connection therewith, said cam .being journaled in and supported solely by the U- shaped clamp and having no positive connection with the fuse terminal support, the lower portions of said U-shaped clamp and cam being adapted to be positioned in the recess in the base of insulating material, the securement of the fuse terminal support to the base of insulating material being adapted to maintain the elements of the fuse holder in assembled relation.

10. A fuse holder combination comprising a base of insulating material, a pair of recesses in said base of insulating material, a pair of fuse terminal supports adapted to engage and support the terminals of a fuse, said fuse terminal supports being secured to the base of insulating material, a pair of bearing members each of which is adapted to engage the under side of one of the fuse terminal supports, said bearing members being supported by the recesses in the base of insulating material, a pair of cams formed of resilient material that bend when they are rotated into the clamping position and thereby provide adequate pressure between the fuse terminals and the fuse terminal supports, and a pair of substantially U-shaped clamps each of which engages the top of one of" the terminals of a fuse supported by the fuse holder and cooperates with a bearing member and a cam to hold a fuse terminal securely to a fuse terminal support, said U-shaped clamps being movable with respect to the fuse terminal supports and having no positive connection therewith, each of said cams being journaled and supported solely by one of the U-shaped clamps and having no positive connection with the fuse terminal supports, the lower portions of the cams and U-shaped clamps being positioned in th recesses in the base of insulating material. the securement of said fuse asospei terminal supports to the base of insulating material serving to maintain the elements of the fuse holder combination in assembled relation.

11. A fuse holder adapted to be supported by a recess in a base of insulating material, comprising a fuse terminal support, said fuse terminal support being adapted to be secured to said base of insulating material, a bearing member adapted to engage the under side of the fuse terminal support, said bearing member being adapted to be supported by the recess in said base of insulating material, a cam formed of resilient material that bends when it is rotated into the clamping position and thereby provides adequate pressure between a fuse terminal and the fuse terminal sup port, and a substantially U-shaped clamp that engages the upper portion of a fuse terminal and cooperates with the bearing member and the cam to hold the fuse terminal securely to the fuse terminal support, said U-shaped clamp being movable with respect to the fuse terminal sup port and having no positive connection therewith, said cam being journaled in and supported solely by the U-shaped clamp and having no positive connection with the fuse terminal support, the lower portions of said U-shaped clamp and cam being adapted to be positioned in the recess in the baseof insulating material, the securement of' the fuse terminal support to the base of insulating material being adapted to maintain the elements of the fuse holder in aswin sembled relation.

12. A fuse holder combination comprising a base of insulating material, a plurality of recesses in said base of insulating material adapted.

to permit the use of the fuse holder combination with fuses of different lengths, a pair of fuse terminal supports adapted to engage and support the terminals of a fuse, a formed portion on at least one of the fuse terminal supports to limit the longitudinal movement of a fuse supported by said fuse holder combination, said fuse terminal supports being secured to the base of insulating material, a pair of bearing members each of which is adapted to engage the under side of one of the, fuse terminal supports, said bearing members being supported by the recesses in the base of insulating material, a pair of cams formed of resilient material that bend when they are rotated into the clamping position and thereby provide adequate pressure between the fuse terminals and the fuse-terminal supports, and a pair of substantially U-shaped clamps each of which engages the top of one of the terminals of a fuse supported by the fuse holder and cooperates with a bearing member and a cam to hold a fus terminal securely to a fuse terminal support, said U-shaped clamps being movable with respect to the fuse terminal supports and having no positive connection therewith, each of said cams being journaled and supported solely by one of the U-shaped clamps and having no positive connection with the fuse terminal supports, the lower portions of the cams and U- shaped clamps being positioned in the recesses in the base of insulating material, the securement of said fuse terminal supports to the base of insulating material serving to maintain the'elements of the fuse holder combination in assembled relation.

HENRY M. STIEGLITZ. 

